Every cell type has a characteristic size that is essential for proper function. Cells grow to a determined size and then either divide or stop growing. However, it remains unclear how cells “know” and regulate their size, and how size influences cell behavior. This NSF-funded project will uncover the mechanisms by which cells sense and respond to changes in size, using the budding yeast Saccharomyces cerevisiae as a model system. Our research focuses on the role of specific signaling proteins (Protein Kinase C and MAP kinase) to understand how they control cell size and adjust cellular processes. To address these questions, we will combine advanced imaging tools with genome-wide analyses to identify key proteins involved in cell size regulation and to understand how size changes impact cell physiology. This project will provide hands-on research opportunities for undergraduate students at Brooklyn College, a public university in New York City. This study will probe the molecular mechanisms that regulate cell size in S. cerevisiae to: 1) identify cell signaling pathway(s) that detects changes in cell size; 2) use genetically encoded multimeric nanoparticles combined with imaging and data analysis to define mechanisms of cytoplasmic and nuclear dilution in growing cells; and 3) utilize high-throughput single-cell transcriptomics to understand the molecular underpinnings of cell size regulation. The project focuses on Protein Kinase C (PKC) and Mitogen-activated protein kin